The present invention relates to an adhesive strip for opening and closing sealed packets containing food products in pieces, particularly sweets and the like, of the type comprising an adhesive strip provided at one end with a non-adhesive gripper tongue and applied in a partially detachable and re-attachable manner to the wall of the packet in correspondence with a shaped cut therein, so as to achieve controlled tearing of the wall during first detachment of the adhesive strip to define an opening through which the products can be taken from the packet, the opening being reclosable by re-attachment of the adhesive strip.